Archive for the ‘Vitamin D’ Category

1. Vesanto Melina, author of Becoming Vegan, kindly passed on a study about vitamin D2 in UV-irradiated mushrooms. 28,000 IU of vitamin D2 was fed to subjects either in the form of a supplement or from mushrooms, one time per week for four weeks. Vitamin D levels increased from 34 to 57 nmol/l in the mushroom group, and from 29 to 58 nmol/l in the supplement group (recommended levels are 40 – 50 nmol/l). The placebo group’s vitamin D2 levels decreased over the course of the study (1).

2. Dole is now making a Portobello Mushroom Powder with the RDA of 600 IU per teaspoon. (Link)

Dr. Michael Greger’s Latest in Clinical Nutrition 6 is now available! In it, he mentions a study about taking vitamin D with meals. I’ve wondered if doing this would help people whose vitamin D levels seem to be resistant to supplementation and so I tracked down the study and updated the VeganHealth.org article, Bones, Vitamin D, and Calcium:

A 2010 study explored this (1). A group of people diagnosed with vitamin D deficiency had been prescribed supplements (some D2 and some D3) and were being monitored by the Cleveland Clinic Foundation Bone Clinic. Some of these patients’ vitamin D levels had not increased to desired levels. Patients with stubborn vitamin D levels were then instructed to take the vitamin D with meals. After 2 to 3 months of taking with meals, the average vitamin D level went from 30 to 47 ng/ml (75 to 117 nmol/l).

This study had no control group, so it is not clear that the vitamin D levels increased due to taking with meals. It could have been simply because their levels took longer to respond to supplements or because they were exposed to more sunlight during the meal period (the time of year studied was not reported). It should also be noted that even though these subjects’ vitamin D levels were more stubborn than other patients, their levels at the beginning of the study were well above those recommended by the Institute of Medicine (16-20 ng/ml or 40-50 nmol/l) the stubborn levels might have been a result of the body regulating vitamin D once it had reached an ideal level rather than an inability to absorb it.

The next logical question is whether vegans should go to the trouble of getting vitamin D3 instead of using vitamin D2. I would suggest that unless you are having problems raising your levels of vitamin D using D2, it is unnecessary.

One bit of advice I have is to take vitamin D with some fat to help increase absorption. I base this only on the fact that vitamin D is fat soluble – I do not know of any trials studying this.

As many of you know, the form of vitamin D made from plants is vitamin D2 (ergocalciferol), whereas the vitamin D from animals foods is vitamin D3. Some research has indicated that, especially in very large doses, D3 is more effective than D2.

I’m going to look into this more with the Vegan Society to hopefully get some details.

In the meantime, Vitashine’s website does not instill confidence with this statement:

“Vitamin D3 (cholecalciferol) is the form of Vitamin D produced by the body after sun exposure. Vitamin D2 (ergocalciferol) supplements are widely sold on the market, but D2 needs to be further converted by the body to become active.”

Vitamin D3 also needs to be further converted by the body to become active. Whether it’s D2 or D3, both the liver and the kidney need to act upon it to convert it, respectively, to calcidiol and then calcitriol. Calcitriol is the active form of the vitamin.

In addition to causing rickets and osteomalacia, vitamin D deficiency can lead to many other diseases including cancer and autoimmune diseases.

Optimal amounts of vitamin D in the blood are between 80 to 100 nmol/l (32 to 40 ng/ml), which was much higher than previously thought.

Many more people than ever before are deficient in vitamin D, especially given the higher levels thought to be optimal.

I also promoted the higher levels for vitamin D, especially given that studies published in the late 2000s on vitamin D listed categories of “insufficiency” and “deficiency” that were in line with the more recent, higher recommendations by some researchers.

But when the Institute of Medicine released their report last November, they did not agree, for the most part, with the three points above. Their Report Brief summarizes their findings (on both calcium and vitamin D):

The committee assessed more than one thousand studies and reports and listened to testimony from scientists and stakeholders before making its conclusions. It reviewed a range of health outcomes, including but not limited to cancer, cardiovascular disease and hypertension, diabetes and metabolic syndrome, falls, immune response, neuropsychological functioning, physical performance, preeclampsia, and reproductive outcomes. This thorough review found that information about the health benefits beyond bone health—benefits often reported in the media— were from studies that provided often mixed and inconclusive results and could not be considered reliable. However, a strong body of evidence from rigorous testing substantiates the importance of vitamin D and calcium in promoting bone growth and maintenance.

The IOM did increase the RDA for vitamin D from 400 IU to 600 IU for adults. But they continue to recommend ideal levels of vitamin D to be between 40 – 50 nmol/l (16 – 20 ng/ml).

I recently finished going back through many of the study summaries on the Bones, Vitamin D, and Calcium page of VeganHealth.org and adjusted them to reflect the IOM’s findings. I also added some information from other vitamin D studies, such as one on tanning beds, another on vitamin D2 vs. D3, and a 2011 report from EPIC-Oxford on vitamin D levels in vegetarians.

The good news is that many vegans who were struggling to raise their vitamin D levels to 80 nmol/l no longer need to worry about that, as 40 – 50 nmol/l is apparently fine and is the recommendation I will be promoting unless the IOM changes its recommendations in the future or there is other overwhelming evidence to do so.

This does not negate the importance of vegans making sure they get a reliable source of vitamin D. As I’ve pointed out many times, I have been contacted by many vegans whose vitamin D levels dropped well below 40 nmol/l and developed symptoms of deficiency. And even without overt symptoms (such as fatigue, or muscle or bone pain), you should not allow your bones to be harmed because you are neglecting vitamin D. My recommendations have stayed pretty much the same – if you are not getting enough sun to produce plenty of vitamin D, you should take about 1,000 IU of vitamin D per day.

1. After reading that QuasiVegan was taking taurine and feeling great, I decided to do some experimenting on myself. I have been taking 1,000 mg of taurine per day for a week. I don’t feel any different – not that I was feeling bad to begin with, but you never know.

A few years ago I tried a similar experiment with carnitine and I noticed myself feeling slightly worse. Also a few years ago, I tried taking methylcobalamin (a form of vitamin B12) rather than cyanocobalamin and felt nothing after going through an entire bottle over the course of a few weeks.

2. Over the holidays I talked to another vegan who was feeling very fatigued, got her D levels tested and they were low, started taking vitamin D, and now feels much better.

I’m not suggesting that how one feels is the best way to determine if taking a supplement is healthy or not, but it might be able to indicate if you had a severe deficiency.

Children in Japan, average age of about 8 to 12, were given 1,200 IU of vitamin D3 or placebo for 4 months and the cases of flu and other symptoms were measured. Children getting vitamin D had 42% less cases of influenza A (.58, .34 – .99). The effect of vitamin D was stronger among kids who had started school later, indicating the ones who started school earlier had built up better immunity.

A reduction in influenza A was not seen in kids who had asthma, although asthma attacks were reduced in those receiving vitamin D by a whopping 83% (.17, 0.04 – .73).

Cases of influenza B did not differ between the two groups, possibly due to different defense mechanisms for preventing influenza A versus B.

I have added some more study summaries to the section on vitamin D2 vs. D3 in the article Bones, Vitamin D, and Calcium on the VeganHealth.org site. My conclusion has remained the same – in amounts of around 1,000 to 2,000 IU per day, vitamin D2 is as effective as vitamin D3.

Here are the new paragraphs:

Glendenning et al. (39) (2009) compared 1,000 IU of D2 vs. D3 in people with vitamin D insufficiency who had hip fractures. After three months, those who supplemented with D3 had a 31% or 52% (depending on how they were measured) greater increase in 25(OH)D levels than those supplementing with D2. However, parathyroid hormone levels did not differ between groups, leading the researchers to question whether the difference in 25(OH)D levels were of biological importance.

Gordon et al. (40) (2008), treated 40 infants and toddlers with vitamin D deficiency. Each were assigned to one of three 6-week regimens: 2,000 IU oral vitamin D2 daily, 50,000 IU vitamin D2 weekly, or 2,000 IU vitamin D3 daily. At the end of the trial, participants’ 25(OH)D levels went from an average of 42.5 to 90 nmol/l (17 to 36 ng/ml), and there were no significant differences between treatment groups.

Thatcher et al. (41) (2009) gave children with rickets one oral dose of 50,000 IU of vitamin D2 or D3. After three days, 25(OH)D levels rose from approximately 50 to 72 nmol/l (20 to 29 ng/ml) for both groups. Calcitriol levels also increased similarly in both groups (by about 70%), however, calcium absorption did not increase, leading the researchers to conclude the rickets were not caused by low vitamin D deficiency. This should not be a surprise since the baseline average level of 50 nmol/l (20 ng/ml) of 25(OH)D should be adequate to prevent rickets.